Basic information about the keys

The keys consist of dichotomous blocks and matrix blocks. While it is clear
how to move through the first, some details on how to use the latter, which might
be less obvious, are discussed below. Information and some additional explanations
are also included. Apart from trying to run a real specimen through a key
with the intent to identify it, some sections provide an alternate way to move
through the taxonomic hierarchy, finding images and basic information on diversity.

Entering the key

The key can be entered from the key entry page (accessible by clicking
Key on the menu bar). It contains a list of entry points. When coming from
the taxa display (Taxa in the menu bar), the key
entry page lists one or more entry links to the current taxon if it is included in a key.

Images

A large view of an image opens in a separate browser window after clicking on the
thumbnail (pop-ups must be allowed for this website). To compare two or even
more images in large view, the individual windows need to be adjusted in size and
shifted appropriately on the screen — sometimes a bit cumbersome.

Dichotomous blocks

These blocks work like couplets in a classical printed key. But they are much
more reliable when moving back to try different branches, in cases where the presented
characters are ambiguous or when reaching a dead end. Although carefully developed,
the keys reflect some of the imperfections of the source literature used for construction.

Matrix blocks

This type of block is truly interactive. It is possible to analyze characters
in any order. It is also possible to reset the states of individual characters
to “not specified” without resetting the whole block to its pristine condition.
A matrix block not only can have three or more branches, but each character
can have more than two states. In characters with numerous states (some of
which might be very similar), it can be very useful to exlude one or more states
rather than selecting one.

Taxa display

Links to taxon pages open in a separate browser tab. Before returning to proceed in the key,
the second browser tab should be closed. Otherwise an error might occur due to conflicting session
information. Should this happen, simply click on Key
on the menu bar of the second browser tab containing the taxon page. One or more links
into the key will be provided for the current taxon. Images used in the key are
usually displayed on the taxon page for the species.

Alternate characters

A few blocks have a link at the top to “Alternate characters,” leading to an “overlapping”
block. This is used in cases where the separation of taxa can follow different paths
(e.g., a more recently developed matrix block to replace an older dichotomous section).

Two branches meeting in one block

This happens very rarely. For example, the first block of the key to the subfamily
Pseudophyllinae can be reached from the section separating the subfamilies of all
Tettigoniidae as well as from the section of Neotropical Tettigoniidae only. Moving
higher in this block only leads to the all-Tettigoniidae section, and the section
on Neotropical subfamilies can only be re-entered separately from the key entry page.

Development

The construction of keys is an ongoing project which currently covers about ten
percent of the taxa down to species level. Many sections of the key are already connected at higher
ranks, thus comprising one single network. Since different parts of the keys are
developed by different people, there can be certain variations in design. And although
various parts are still under construction, some partially useful blocks are already
shown with an “under development” note.